Tropical Storm Isaac weakens while Florance threatens US Carolinas

As the potentially dangerous category 4 Hurricane Florence makes its way towards North Carolina's barrier islands, now under a mandatory evacuation order, Tropical Storm Isaac appears to be getting less organized as of Tuesday night as it tracks toward the Caribbean.

The National Hurricane Center no longer thinks Isaac will be near hurricane strength as it nears the Lesser Antilles on Thursday, and a hurricane watch was dropped for the islands. Tropical storm watches and warnings continue, however.

According to the National Hurricane Center, as of 10 p.m. CDT Tuesday Tropical Storm Isaac was located about 580 miles east of Martinique and was moving west at 16 mph.

Isaac's winds fell to 65mph. The hurricane center said gradual weakening is expected in the next few days as Isaac runs into wind shear.

A tropical storm warning is in effect for Martinique, Dominica and Guadeloupe.

A tropical storm watch is in effect for Antigua, Montserrat, St. Kitts and Nevis, Saba and St. Eustatius.

Forecasters said tropical storm conditions will be possible in the warning area by Thursday morning.

Where is Isaac heading? The hurricane center thinks Isaac will continue heading west for the rest of the week.

Isaac is a small storm, which makes intensity forecasting particularly challenging. Isaac is forecast to weaken as it enters the Caribbean because of increasing wind shear. It may not be able to recover from that and could dissipated altogether by Day 5.

In the meantime, Florence is expected to bring devastating winds, storm surges and flooding.

The storm could bring massive amounts of rain, with some estimates putting the projected totals at 30 inches as it stalls out over the East Coast. Officials said the storm could produce "catastrophic flash flooding."

North Carolina's barrier islands are now under a mandatory evacuation order. The order covers the entire coastline from the South Carolina to the Virginia borders.

Hurricane and storm surge warnings are now in effect for parts of North and South Carolina as Hurricane Florence makes its way towards the East Coast with sustained winds of 140 mph.